1. Field of the Invention
This invention relates to a process for the production of phthalazineacetic acid ester derivatives of the formula ##STR3## wherein R is (C.sub.1 -C.sub.4)alkyl.
This invention also relates to the novel compound 1-hydrazino-1,2,3,4-tetrahydro-4-oxo-phthalazineacetic acid of the formula ##STR4## which is an intermediate formed in the process of this invention and which is useful for the production of phthalazineacetic acid ester derivatives of formula IV. The compounds of formula IV are useful for the preparation of certain heterocyclic oxophthalazinyl acetic acids and esters thereof.
2. General Background
Certain heterocyclic oxophthalazinyl acetic acids and esters of the general formula ##STR5## wherein X is oxygen or sulfur, Z is a covalent bond, O, S, NH or CH.sub.2 ; R.sub.1 is hydroxy, or a prodrug group; R.sub.2 is a heterocyclic group, R.sub.3 and R.sub.4 are hydrogen or the same or a different substituent, and R.sub.5 is hydrogen or methyl, as well as certain pharmaceutically acceptable salts thereof and their usefulness as inhibitors of aldose reductase are disclosed in pending U.S. patent application Ser. No. 916,127, filed Oct. 7, 1986 which is a divisional application of Ser. No. 796,039, filed Nov. 7, 1985, now abandoned, and which is assigned to the assignee hereof and, inter alia, in the corresponding published European Patent Application No. 222,576, published May 20, 1987, wherein the applicant is the assignee hereof. The teachings thereof are incorporated herein by reference. That patent application also discloses a process for the production of certain phthalazineacetic acid esters which comprises reacting certain phthalic anhydrides with either (carbethoxymethylene)triphenylphosphorane or (carbomethoxymethylene)triphenylphosphorane in the Wittig reaction and then reacting the resulting acetic acid ester derivatives with hydrazine in, preferably, an aqueous solvent at 40.degree. to 120.degree. C.
A process for preparation of (Z)-3-oxo-1(3H)-isobenzofuranylideneacetic acid from phthalic anhydride by reacting phthalic anhydride with potassium acetate and acetic anhydride is disclosed by Schroeder, H. E., et al., J. Amer. Chem. Soc., 78, 446 (1956). and acetic anhydride is disclosed by Schroeder, H. E., et al., J. Amer. Chem. Soc., 78, 446 (1956).
A process for the preparation of certain phthalazones by reacting orthophthalaldehydic acid or phthalonic acid with hydrazine is disclosed by Vaughan, W. R. and Baird, Jr., S. L., J. Amer. Chem. Soc., 68, 1314 (1946).
Foldeak, S., et al., Chemical Abstracts 72: 100626 p (1970), Khim.-Farm. Zh, 3(12), 5 (1969), disclose, inter alia, a process for the preparation of 4(3H)-phthalazone-1-acetic acid by heating (Z)-3-oxo-1(3H)-isobenzofuranylideneacetic acid for two (2) hours with N.sub.2 H.sub.4 --H.sub.2 SO.sub.4 in aqueous KHCO.sub.3.